Inspecting apparatus which measure an electrical characteristic of multiple IC chip (hereinafter, devices) formed on a semiconductor wafer (hereinafter, simply called wafer) have, for example, a loader unit and a prober unit. The loader unit carries a wafer. The prober unit measures the electrical characteristic of each device on the wafer delivered from the loader unit The loader unit is provided with a cassette mounting unit, a pincette, and a sub-chuck. The cassette mounting unit allows wafers to be mounted thereon cassette by cassette. The pincette carries a wafer to the loader unit. The sub-chuck performs pre alignment to align the direction of a wafer based on its ori-fla (orientation flat) while the wafer is held and carried by the pincette. The prober unit is provided with a main chuck (stage), an alignment mechanism and a probe card The main chuck receives a wafer which has undergone pre-alignment from the pincette, and mounts it thereon. The main chuck is movable in X, Y, Z and θ directions. The alignment mechanism precisely positions a wafer on the main chuck. The probe card has a probe needle which contacts an electrode pad on the wafer in such a manner as to be electrically conducted therewith after positioning.
The tester of a wafer inspecting apparatus has a test head. The test head is electrically connected with the probe card attached to the head plate of the prober unit. The test head mediates transmission/reception of a signal between the tester and the probe card. Inspection for the electrical characteristic of a device formed on a wafer is carried out by transmitting/receiving a signal between the probe card and the tester.
In a case where wafer inspection is carried out at a high temperature or a low temperature, the probe itself expands and contracts by the temperature, so that it is necessary to heat (preheat) or cool the probe before the inspection is started.
When preheating is performed with the probe being brought closer to (but does not come in contact with) a heat source (chuck), several minutes to several ten minutes are required to cause the probe to be at a target temperature. When preheating is performed with the probe contacting a wafer, which is an inspection target on the chuck, the required time can be reduced, but there is a large possibility that the probe or the wafer is damaged due to thermal deformation of the probe card and expansion and contraction of the probe.
There is proposed a technique which substantially stabilizes the relative position of the stage to the probe card from the beginning to the end of a temperature test in accordance with expansion and contraction of the probe needle. For example, Japanese Patent Application KOKAI Publication No. H11-176893 (hereinafter, Patent Literature 1) discloses a method of detecting at least either one of the temperature of the probe card and pressure that the probe card contacts a connection member, and of connecting the position of the heating stage based on the obtained value.
According to the technique disclosed in Patent Literature 1, however, it is necessary to dispose a temperature sensor or a pressure sensor on the probe card or therearound to detect a temperature or pressure. Thus, the structure around the probe card becomes complex, and the cost of the wafer inspecting apparatus increases, and it requires a lot of maintenance time.
Japanese Patent Application KOKAI Publication No. 2000-299360 (hereinafter, Patent Literature 2) discloses a technology which employs heating/cooling means for heating/cooling a wafer and a wafer-probe-pin module with separate individual temperature control systems. This technology is a technology which detects a difference in thermal expansion amounts between a wafer and a wafer-pin module by a differential transmission or the like, and performs negative feedback control on the heating/cooling means for the wafer-probe-pin module in such a way that the difference becomes eliminated to make the thermal expansion amount uniform.
According to the technology disclosed in Patent Literature 2, however, independent heating/cooling means is required for the probe card in addition to heating/cooling means for a wafer. Therefore, the wafer inspecting apparatus becomes complex, and the cost thereof increases, and it requires a lot of maintenance time.